Automatic material discrimination by using computer tomography

Abstract

Method and apparatus are provided for combining information obtained from CT and Coherent Scatter Computed Tomography to better determine whether there are dangerous materials in the baggage or not. Hence, the attenuation coefficient and the diffraction pattern of the item of baggage are used to determine whether the baggage should be cleared.

1 . An inspection system for detecting a specific material of interest in an item of baggage, the inspection system comprising:
 a first scanner system for determining an attenuation coefficient of the item of baggage;   a second scanner system for determining a diffraction pattern of the item of baggage, wherein the second scanner system is a coherent-scatter computed tomograph; and   a calculation unit connected to the first and second scanner systems for identifying a presence of the specific material of interest in the item of baggage on the basis of the attenuation coefficient and the diffraction pattern.   
   
   
       2 . The inspection system of  claim 1 ,
 wherein the first and second scanner systems are arranged at a distance from each other.   
   
   
       3 . The inspection system of  claim 1 ,
 wherein the first scanner system is a computed tomograph (CT) applying a fan-shaped or cone-shaped radiation beam to the item of baggage; and   wherein the coherent-scatter computed tomograph is configured to apply a fan shaped radiation beam to the item of baggage.   
   
   
       4 . The inspection system of  claim 1 ,
 wherein the first scanner system and the second scanner system are realized as one scanner system;   wherein the one scanner system has one source of radiation and one detector system;   wherein the one scanner system has a first aperture system which is positionable between the item of baggage and the source of radiation such that a cone-shaped radiation beam is applied to the item of baggage;   wherein the one detector system is adapted to detect the attenuation coefficient of the item of baggage when the cone-shaped radiation beam is applied to the item of baggage;   wherein the one scanner system has a second aperture system which is positionable between the item of baggage and the source of radiation such that a fan-shaped radiation beam is applied to the item of baggage;   wherein the one detector system is adapted to detect the diffraction pattern of the item of baggage when the fan-shaped radiation beam is applied to the item of baggage.   
   
   
       5 . A method of inspecting an item of baggage, the method comprising the acts of:
 scanning the item of baggage at a first scanner stage with a first radiation beam for determining an attenuation coefficient of the item of baggage;   determining whether there is a suspicious region in the item of baggage on the basis of the attenuation coefficient;   scanning an area of the item of baggage including the suspicious region at a second scanner stage, wherein the scanning is performed with a second radiation beam for determining a diffraction pattern of the area using a coherent-scatter computed tomograph;   determining whether there is a dangerous material in the item of baggage on the basis of the diffraction pattern; and   generating a signal indicative of the dangerous material.   
   
   
       6 . (canceled) 
   
   
       7 . (canceled) 
   
   
       8 . (canceled) 
   
   
       9 . The method of  claim 5 , wherein the attenuation coefficient is determined with a computed tomograph (CT) where the first radiation beam is cone-shaped; and
 wherein the second radiation beam is fan-shaped.   
   
   
       10 . A computer readable medium comprising a computer program wherein, when the computer program is executed on an inspection system for inspecting items of baggage, the inspection system performs the acts of:
 scanning the item of baggage at a first scanner stage with a first radiation beam for determining an attenuation coefficient of the item of baggage;   determining whether there is a suspicious region in the item of baggage on the basis of the attenuation coefficient;   scanning an area of the item of baggage including the suspicious region at a second scanner stage, wherein the scanning is performed with a second radiation beam for determining a diffraction pattern of the area using a coherent-scatter computed tomograph;   determining whether there is a dangerous material in the item of baggage on the basis of the diffraction pattern; and   generating a signal indicative of the dangerous material.